365.2425 is the exact value computed by the formulas found in the
Gregorian calendar (a very good approximation of reality).
365.2422 is the physical reality of how long it actually takes (but
there are tiny wobbles in it).
http://www.timeanddate.com/date/leapyear.html
> -----Original Message-----
> From: Bruce Momjian [mailto:pgman@candle.pha.pa.us]
> Sent: Friday, July 22, 2005 12:03 PM
> To: Bruno Wolff III
> Cc: Dann Corbit; Greg Stark; Tino Wildenhain; Tom Lane; PostgreSQL-
> development; Marc G. Fournier
> Subject: Re: [HACKERS] Imprecision of DAYS_PER_MONTH
>
> Bruno Wolff III wrote:
> > On Thu, Jul 21, 2005 at 13:47:29 -0700,
> > Dann Corbit <DCorbit@connx.com> wrote:
> > > In round figures:
> > >
> > > Since there are 365.2422 days per tropical year, there are
31556926
> > > seconds per year (give or take leap seconds).
> > >
> > > Ref:
> > > http://www.grc.nasa.gov/WWW/K-
> 12/Numbers/Math/Mathematical_Thinking/cale
> > > ndar_calculations.htm
> >
> > According to the current calendar (again ignoring leap seconds)
there
> > are exactly 365.2425 days per year on average. I think it makes
sense to
> use
> > this number when dealing with calendar years and months.
>
> Someone came up with 365.2422. Which is better?
>
> --
> Bruce Momjian | http://candle.pha.pa.us
> pgman@candle.pha.pa.us | (610) 359-1001
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